The key technology system construction and application for accurate horizon prediction of HTHP wells in the Western South China Sea
The Yinggehai-Qiongdongnan Basin in the Western South China Sea is one of the three major high-temperature high-pressure(HTHP)marine areas in the world.Exploration operations in this area face challenges such as high formation temperatures,high pressures,and abnormal pressures,which result in a narrow drilling safety pressure window.One of the necessary conditions for safe drilling is the precise prediction of target depth and formation pressure.This allows for the proper placement of casing,ensuring sufficient safety pressure window to drill into the target interval.At present,the conventional methods for depth and pressure prediction are based on the time-depth relationship and formation correlation of adjacent wells.However,these methods suffer from low accuracy and poor resolution and cannot address the issue of lateral heterogeneity in the formation.To overcome these challenges,key technologies for accurate depth and pressure prediction in HTHP exploration wells have been systematically developed based on existing technologies in the Western South China Sea.A set of key technological systems,based on Conventional Sonic Logging While Drilling,Vertical Seismic Profile(VSP)Logging,and IriSphere Look-Ahead-While-Drilling Service,has been summarized.These provide robust technical support for the optimization of wellbore structure of HTHP wells,significantly improving the geological completion rate and operational efficiency,reducing the cost pressure of HTHP exploration operations,and promoting the safe and smooth implementation of HTHP exploration operations in the Western South China Sea.The research results provide technical references for accurate prediction of target layer depths during the drilling of HPHT wells.
Yinggehai-Qiongdongnan BasinHTHPSonic logging while drillingVertical seismic profileIriSphereAccurate horizon prediction